Why erased RuntimePath directory?

[pobearm]

The RuntimePath directory is erased and recreated at each Start(). In func (ep *EmbeddedPostgres) Start():

if err := os.RemoveAll(ep.config.runtimePath); err != nil {
	return fmt.Errorf("unable to clean up runtime directory %s with error: %s", ep.config.runtimePath, err)

}

Why we earse this directory every time Start? It cause very slow when starting our app. Any ideas of use check instead of erase? Or add some options.